Large amounts of organic waste are generated annually from agricultural plantations, animal farms, mills, food processing plants and industrial plants. The amount of organic waste generated has been increasing each year as the agro-food industries expand. Consequently, the disposal of these wastes has been a major concern in recent years.
Composting has been recognized as an effective way to address the problem of organic waste disposal. Composting converts organic waste into fertilizers by a microbiological process. However, the natural composting of organic waste by naturally occurring micro-organisms can take up to months and even years to mature, and typically results in a product with relatively low nitrogen, phosphorous and potassium (NPK) values because large amounts of ammonia, ammonium ions, phosphorous, potassium and essential trace elements are lost to the environment during composting period. Such losses decrease the amount of essential elements in the final composted product. Organic fertilizers with low NPK values are less useful and less commercially valuable.
To increase the speed of composting, the organic wastes are aerated either by agitating the waste or by supplying air to the waste. There are many household composting systems known in the art that comprise of agitated or rotating drums supplied with either natural aeration or air blowers. There are also other household systems that include worms or microbes to increase the speed of composting. Aeration aids in the aerobic digestion of organic waste, thereby preventing the production of foul odors when anaerobic conditions set in. While the composting period is reduced to a few weeks, these systems however cannot ensure homogeneous aeration and pockets of anaerobic micro-environments tend to exist.
On the commercial front, there are many known commercial composting systems including windrow composters and tunnel composters. Although windrow and static pile composting systems can handle large amounts of organic waste, they require an equally large amount of land and their use is thus limited to the outskirts of urban areas.
Tunnel composting systems and in-vessel systems, on the other hand, are unable to achieve large-scale operation. Even though these systems may enable at most mid-scale decomposition in an enclosed space, they require high energy consumption which makes them relatively more expensive. Further, the organic fertilizers produced are of inconsistent quality. Known vessel composting systems may provide good mixing capabilities at small volumes of up to 3 tonnes. However, scale-up is problematic because of the increased presence of pockets of anaerobic micro-environments in vessels larger than 3 tonnes. These dead spaces not only result in the production of foul odors, but also compromise the quality of the organic fertilizers produced.
There is yet another known composter which comprises a plurality of paddles to aid in the mixing of compost material. However, such composters consume large amounts of energy and are not economical.
There is therefore a need to provide an apparatus and system for treating organic waste that overcomes, or at least ameliorates, one or more of the disadvantages described above.